One-minute algae: new source of oil?

New process can quickly turn algae into biocrude. But it's not the same as nature's crude oil.

Business Wire/File

Algae strains in large photobioreactors are evaluated under varying conditions, including varying temperatures, light levels and nutrient concentrations, in this 2010 file photo taken at ExxonMobil's greenhouse in La Jolla, Calif.

If only 10% of the supposed energy breakthroughs panned out, there would be cheap energy galore for everyone. But since we started running cars on oil 100 years ago, how many truly disruptive technologies have there actually been in the area of transportation fuel? There have been improvements, yet we are still running most of our cars on oil.

But this past week brought news of another supposed breakthrough in producing fuel from biomass. Researchers at the University of Michigan announced that they had sped up the process that Mother Nature used to convert algae into oil:

ANN ARBOR-It looks like Mother Nature was wasting her time with a multimillion-year process to produce crude oil. Michigan Engineering researchers can "pressure-cook" algae for as little as a minute and transform an unprecedented 65 percent of the green slime into biocrude."We're trying to mimic the process in nature that forms crude oil with marine organisms," said Phil Savage, an Arthur F. Thurnau professor and a professor of chemical engineering at the University of Michigan.

Here is what you need to know about this supposed breakthrough.

It is true that crude oil was originally produced primarily from the remains of ancient algae. The algae died, sunk to the bottom of lakes and shallow seas, and were buried over time. As the organic matter became buried deeper within the earth, the heat and pressure increased over time until it was converted first into kerogen, and then into crude oil. If the material experienced too much heat, it was cracked into natural gas.

So one might expect that this process could be sped up in the lab, and in fact over the years many have claimed to produce "crude oil" from biomass quickly by adding heat and pressure. But what is generally not made clear is that this so-called crude oil that is being rapidly produced from biomass is very different from the crude oil that Mother Nature produced.

When biomass is heated up rapidly to above 500 degrees C, fast pyrolysis occurs. The cellulose, lignin, and hemicellulose in biomass breaks down in seconds into a pyrolysis oil and char. This pyrolysis oil is often called bio-crude, and some have gone so far as to suggest that it is essentially the same as crude oil. However, the composition is very different.

Unlike crude oil, the components in pyrolysis oil contain a lot of oxygen. These compounds include aldehydes, carboxylic acids (like acetic acid), ketones, alcohols, sugars, and pyrolytic lignin, and their volumetric energy content tends to be far lower than that of petroleum. Further, these are generally short molecules, and when they are refined to transportation fuel a good portion of the oil is lost as carbon dioxide and water in the process.

Pyrolysis oil is typically produced from wood chips, and a number of companies have been making pyrolysis oil for years. However, if you used algae as the feedstock for a pyrolysis reactor, you would expect that the output would be similar compounds to what is produced with wood feedstock.

Therefore, my expectation would be that the Michigan researchers are producing pyrolysis oil and not crude oil. And the press release announcing the results indicated as much: "Before biocrude can be fed into the existing refinery system for petroleum, it needs pre-refining to get rid of the extra oxygen and nitrogen atoms that abound in living things."

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While I don't want to downplay this research, the problems with trying to speed up what nature did for free are that the energy and pressure inputs are costly, and the product isn't crude oil. Thus, my conclusion is that it is interesting research, but far from an energy breakthrough. Any obviously energy-intensive process for producing transportation fuel will ultimately find it very difficult to compete with crude oil.